Chair

ABSTRACT

A CHAIR HAVING THE LENGTH OF THE SEAT APPROXIMATELY EQUAL TO THE DISTANCE FROM THE FRONT OF THE SEAT TO THE CHAIR TO THE FLOOR, WITH THE SACRAL BRACE TILTING BACKWARD AT AN ANGLE OF 95* FROM THE FLOOR TO THE SACRAL BRACE TO SUPPORT THE SACRUM, THE SEAT TILTING DOWNWARDLY FROM THE FRONT OF THE SEAT TO THE BACK OF THE SEAT BETWEEN FIVE AND EIGHT DEGREES OF DECLINATION, ARM RESTS PARALLEL TO THE SEAT WITH THE RELATIONSHIP OF THE DISTANCE FROM THE BACK OF THE ARM REST TO THE BACK OF THE SEAT AND THE BACK OF THE SEAT TO THE FLOOR AT A RATIO OF THREE TO FIVE, AND THE BACK OF THE CHAIR TILTING BACKWARD AT AN ANGLE OF ONE HUNDRED DEGREES FROM THE FLOOR TO THE BACK OF THE CHAIR.

Sept. 20,- 1971 ;T. K, ARBUTHNOT CHAIR Filed March 24, 1969 I N VEN'IOR.

1 Z I THEODORE mARau-rmm' BY 7 f ATTURNEY United States Pat fi 3,606,464CHAIR Theodore K. Arbuthnot, 3233 NE. 34th St., Apt. 1210, FortLauderdale, Fla. 33308 Filed Mar. 24, 1969, Ser. No. 809,562 Int. Cl.A47c 7/00, 7/20 US. Cl. 297-460 6 Claims ABSTRACT OF THE DISCLOSURE Achair having the length of the seat approximately equal to the distancefrom the front of the seat to the chair to the floor, with the sacralbrace tilting backward at an angle of 95 from the floor to the sacralbrace to support the sacrum, the seat tilting downwardly from the frontof the seat to the back of the seat between five and eight'degrees ofdeclination, arm rests parallel to the seat with the relationship of thedistance from the back of the arm rest to the back of the seat and theback of the seat to the floor at a ratio of three to five, and the backof the chair tilting backward at an angle of one hundred degrees fromthe floor to the back of the chair.

BACKGROUND OF THE INVENTION This invention relates to a new and improvedchair, and, more particularly, to a chair supporting ones spine in aposition when seated that is similar to the position of the personsspine in a standing position.

As is perhaps well-known, when a human is in a standing position, from aphysiological anatomical standpoint, he provides a freedom of functionfor all organs Within the thorax and abdomen. The same freedom offunction has not been made available to humans sitting in chairsdesigned in the past. Such chairs have been designed in an attempt toprovide only structural support of a human. The

previously designed chairs have not incorporated all the essentialelements that are necessary to provide the freedom of function of ahuman in a seated position.

SUMMARY OF THE INVENTION The present invention relates to a new andimproved chair having five essential design features to provide a humanwith the same freedom of function in a seated position as he has in astanding position. The chair has a ratio of approximately one to one(1:1) between the distance from the front of the seat of the chair tothe floor and the distance of the front of the seat to the back of theseat, a sacral brace tilting backward at an angle of ninetyfive degreesfrom the floor to the sacral brace to support the sacrum and in turnsupport the spine, the seat tilting downwardly from the front of theseat to the back of the seat between five and eight degrees ofdeclination, arm rests parallel to the seat with a ratio of three tofive between the height of the arm rest above the back of the seat andthe height of the back of the seat above the floor support, and the backof the chair tilting backward at an angle of one hundred degrees fromthe floor to the back of the chair. The back of the chair may provide aneck rest or head rest which would extend anteriorly from three to fourinches to correspond with the anterior curve at the occupants neck.

It is an object of this invention to provide a chair for a humanproviding the same freedom of function in the sitting position, as hewould obtain in a standing position.

It is another object of this invention to provide a chair with a ratioof approximately one to one between the distance from the front of theseat of the chair to the floor and the distance of the front of the seatto the back of the seat.

Another object of this invention is to provide a chair with a sacralbrace tilting backward at an angle of ninetyfive degrees from the floorto the sacral brace.

Another object of this invention is to provide a chair with a seattilting downwardly from the front of the seat to the back of the seatbetween five and eight degrees of declination.

A further object of this invention is to provide a chair with arm restsparallel to the seat with a ratio of three to five between the height ofthe arm rests above the back of the seat and the height of the back ofthe seat above the floor.

Another object of this invention is to provide a chair with the back ofthe chair tilting backward at an angle of one hundred degrees from thefloor to the back of the chair.

An additional object of this invention is to provide a chair with all ofthe features set forth in the objects hereinabove.

In accordance with these and other objects which will be apparenthereinafter, the instant invention will now be described with particularreference to the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING In the drawing:

FIG. 1 is a side view of the chair partially cut away illustrating ahuman therein;

FIG. 2 is a partial side view of the chair showing various designangles; and

FIG. 3 is a perspective View of the sacral brace.

DESCRIPTION OF THE PREFERRED EMBODIMENT 'Referring now in detail to thedrawing, wherein an embodiment of the invention is shown, and,referring, particularly, to FIG. 1, the chair, generally designated atnumeral 2, is placed on floor 4. The floor also supports the feet of theoccupant of the chair 2. The chair includes legs, 6 and 8 are shown, aseat base member 10, a seat 12, a back or back brace 14, a sacral brace16, and arm supports, arm support 1 8 is shown. The back brace 14 mayinclude a neck support or neck and head support extension 20.

The chair shown in FIG. 1 includes five basic design features that takeinto account some very pertinent anatomical facts, as well as the greatflexibility of body tissues. The human is not locked in the chairillustrated in the drawing, in any one position and he may changeposition without discomfort. It should be noted that in the standingposition the normal spine has three curves, two anterior and oneposterior. The first anterior curve begins at the base of the skull andextends to the fifth cervical vertebra. The second anterior curve beginsat the junction of the third and fourth lumbar vertebrae and extends tothe coccyx. The posterior curve begins at the first dorsal and extendsto the third lumbar vertebra. In the standing position the contents ofthe thorax and abdomen are hanging normally from. their spinal or otherattachments and are free to perform their physiological functionswithout hindrance from compression or circulatory obstructions. Thechair 2 provides support for the person in the sitting position. thatclosely approximates the humans standing position. The average livingroom or den chair does not provide such support because it is soconstructed as to force the spine into one big posterior curve. In theaverage chair the contents of the thorax and abdomen are subject to acompression which is not desirable, particularly to those humans whohave disabilities of the heart, lungs and other physiological conditionswhich require the best of circulation. To negate this undesirablefeature, chair 2 permits the spine to assume a position more nearlyapproximating the standing position. The occupant is completely at restwithout muscle tension supporting various parts of his body.

Proper support for an occupant of a chair is provided in the disclosedchair design. In the past, a number of chairs have been built with crossbars at the level of the anterior lumbar curve, that is, the hollow ofones back. Some chairs have been built with a cross bar at a higherposition in the dorsal area of ones back. Such cross bars, positioned atthe anterior lumbar curve or in the dorsal area, may force an occupantof the chair into an erect posture but that type of bracing action willalso lock the muscles of the occupants back into steady tension. If onesmuscles are held in steady tension over a long period fatigue will setin. The proper basis of spinal support is at the sacrum. If a personsits on a bench, completely relaxed, he will have a very slumpedposition and his spine will show one big posterior curve from the neckto the coccyx. When the surface of the sacrum is firmly supported theperson may relax but he will be unable to slump. His back muscles willnot be in tension and no fatique will set after sitting for a relativelylong period of time. To design the type of back support disclosedherein, a sacral brace 16 is incorporated in the chair as shown in thedrawing. The sacral brace 16 slopes backward at a ninety-five degreeangle to the floor 4 as shown in FIG. 2. The anterior face of the sacralbrace may be bonded with a polyurethane foam from /8" to A" thick.

It should be noted that the distance from the hollow of the bended knee,shown at point 22, to the floor 4 Will be the same as the distance fromthe hollow of the knee, shown at point 22, to a line at the base of thesacrum 24. Most of todays living room or den chairs average between 19and 21 inches in seat depth. Divan seats will usually be about 23inches. A person whose knee to floor measure is only 15 to 18 inchescannot sit with his sacrum against the back of the chair. The spine willassume the one big posterior curve. Since people come in many differentsizes, in order to design a chair that will place the sacrum of a personagainst a sacral brace, different size chairs must be constructed. Inthe design of the disclosed chair 2, the measurement of the seat fromthe front of the seat to the back of the seat in relation to themeasurement from front of the seat to floor will be approximately a oneto one ratio. This ratio will remain constant for all size chairs. Theheight of the front of the seat 12 from the floor is approximately equalto the distance from the front of the seat 12 to the back of said seat.An allowance of up to one inch may be used in designing the seat lengthto accommodate the extra flesh lateral to the sacrum.

Seat 12 slopes downwardly from the front edge in order to prevent thenecessity of the occupant to tense his muscles to maintain thisposition. When the seat is horizontal the occupant would have a tendencyto lean forward. Therefore, to make the occupants position one of arelaxed person, that is, relatively free of muscle tension, especiallyin his back muscles, the seat 12 of the chair 2 slopes downwardly fromthe front of the chair. The proper angle of declination from front ofthe chair to the back of the chair is between five to eight degrees. Theparticular angle used may be left to the art of the designer. Thepreferred angle is between six and seven degrees. For example, the angleof declination may be 6.4 degrees which holds the occupant in the seatin a relaxed erect position.

The chair has arms 18 to support the occupant. If arms are not providedat a sufiicient height, the muscles of the shoulder girdle will impel ageneral slump. The arms 18 of the chair 2 should be high enough for theelbow to rest on the arms to support the shoulder girdle without tensionon the shoulder muscles. The arms 18 of the chair 2 should parallel theupper surface of the seat 12 and should extend for at least 16 inchesfrom the back rest 14. Longer arms may be desirable but can be left tothe art of design. The height of the arm from the back of the seat inrelation to the height of the back of the seat from the floor is aconstant ratio of 3 to 5. This ratio is held for all size chairs.

An important consideration is constructing the shape of the back 14 ofthe chair 2 is that the posterior curve of the back of an occupantshould rest comfortably in the chair 2 Without undue pressure in any onespot. This may be achieved by designing a curve running from the top ofthe sacral brace 16 to near the top of the occupants back at point 26,using relatively firm upholstering or having a straight back thicklypadded with a soft upholstering which Would permit the back to settleinto its proper curve. Also it may be desirable to have the upper fourinches of the back, shown at 20, with a pad extending three to fourinches forwardly to accommodate the anterior curve in the neck region orto serve as a head rest.

The back of the chair is sloped backwardly at an angle. A tangent drawnthrough the curve-d front side of the back of the chair as shown in FIG.2 intersects the floor 4 at an angle of one hundred degrees as shown inFIG. 2. The line drawn through the sacral brace intersects the floor atan angle of ninety-five degrees. Therefore, the five degree differencebetween the angle of the sacral brace and the back of the chair providesthe bracing effect to support the occupant.

The details of the sacral brace 16 are shown in FIG. 3. With the chairsoccupant seated in seat 12 and with the sacrum and buttocks of theoccupant placed against the sacral brace 16, the occupant is in acompletely relaxed position. The sitting posture is near the occupantsstanding posture. The chair allows the body to be adjusted in the chair,the chair 2 does not lock the occupant in one position.

The instant invention has been shown and described herein in what isconsidered to be the most practical and preferred embodiment. It isrecognized, however, that departures may be made therefrom Within thescope of the invention. Therefore, the instant invention is not to belimited to the details discussed herein, but to be accorded the fullscope of the claims so as to embrace any and all equivalent apparatusand articles.

What is claimed is:

1. A chair comprising:

supporting members,

a seat member connected to said supporting members,

a back member connected to said seat member, said back member includinga concave front supporting surface adapted to support the back of aperson occupying the chair, the greater portion of said supportingsurface generally slopes upwardly and rear- Evardly when viewed from apoint on said seat mema sacral brace connected to said back memberadapted to make contact with the sacrum of the person occupying thechair to support the sacrum of the person, said sacral brace slopesupwardly and rearwardly when viewed from a point on said seat member.

2. A chair as set forth in claim 1 wherein,

said seat slopes downwardly from the front of said seat to the back ofsaid seat at an angle between five and eight degrees.

3. A chair as set forth in claim 2 wherein,

the relationship of the length of said seat to the height of the frontof the seat from a floor is approximately a one to one ratio.

4. A chair comprising:

supporting members,

a seat member connected to said supporting members,

a back member connected to said seat member,

a sacral brace connection to said back member for contact with thesacrum of an occupant of the chair to support the sacrum of theoccupant,

the front supporting surface of said back member is concave when theback of the occupant is supported by said back member,

a line drawn tangentially to the most rearward portion of said concavesurface intersects a horizontal line at an angle sloping rearward from apoint below an upper point on said tangential line,

a line drawn parallel to the front surface of said sacral braceintersects a horizontal line at an angle sloping rearward from a pointbelow an upper point on said parallel line,

said seat slopes downwardly from the front of said seat to the back ofsaid seat at an angle between five and eight degrees,

the relationship of the length of said seat to the height of the frontof the seat from a floor is approximately a one to one ratio, and

arm rests connected to said chair, the relationship of the height of thearm rest from the back of the seat to the height of the back of the seatfrom the floor is approximately a three to five ratio.

5. A chair as set forth in claim 4 wherein,

said angle sloping rearward from a point below an upper point on saidtangential line is approximately one hundred degrees.

6. A chair as set forth in claim 5 wherein,

said angle sloping from a point below an upper point on said parallelline is approximately ninety-five degrees.

References Cited UNITED STATES PATENTS 458,140 8/1891 Bangs 297460856,058 4/1907 Hanger 297-460 1,210,223 12/1916 Silbert 297460 1,917,2647/1933 Kellogg 297459 CASMIR A. NUNBERG, Primary Examiner US. Cl. XR,

